There's a limit to how precise I can be here without violating the "no hacking" ban, but...
The script is 1. compressed and 2. uses a relative alphabet encoding (we have the encoding table for the English version, but, as far as I know, not for the Japanese). Fortunately, we have a working decompresser, so the big obstacle is the encoding table. Building it is going to require the extraction of the Japanese font graphic (probably not difficult once we find it), a bunch of kanji/kana IDs, and possibly some screen caps of the Japanese version in action to help in figuring out any double-byte encoding they may have used.
(Before anyone asks, I'm pretty sure I know how the basis for our existing English script was dumped, and that utility doesn't have the Japanese encoding table either.)
So: it's doable, but I can't do it working by myself (and I expect that if you could, you would already have offered)--we need either utunnels (who, if I'm not mistaken, has both the Japanese CDs and the mad kanji skillz necessary to build the table), or someone with the Japanese CDs who's able to follow my instructions to do the dump and someone to work on the kanji.